The invention relates to a process for partial oxidation of a liquid or solid and/or a gaseous hydrocarbon-containing fuel using a multi-orifice burner.
In particular, the invention relates to a process for partial oxidation of a liquid or solid and/or a gaseous hydrocarbon-containing fuel wherein an oxygen-containing gas, a liquid or solid hydrocarbon-containing fuel and/or a hydrocarbon gas are supplied to a gasification zone through a multi-orifice burner comprising a concentric arrangement of 4 annular passages or channels and 1 central passage or channel, and wherein autothermically a gaseous stream containing synthesis gas is produced under appropriate conditions.
The oxygen-containing gas is usually air or pure oxygen or a mixture thereof. In order to control the temperature in the gasification zone a moderator gas (for example steam or carbon dioxide) can be supplied to said zone.
Synthesis gas is a gas comprising carbon monoxide and hydrogen, and it is used, for example, as a clean medium-calorific-value fuel gas or as a feedstock for the synthesis of methanol, ammonia or hydrocarbons, which synthesis yields gaseous hydrocarbons and liquid hydrocarbons such as gasoline, middle distillates, lub oils and waxes.
In this specification and claims the terms "gaseous hydrocarbons" and "liquid hydrocarbons" will be used to refer to hydrocarbons that are at gasifier feed pressure and temperature gaseous and liquid, respectively.
A known method for producing synthesis gas is partially oxidizing a particulate solid fuel, such as coal, charcoal or petroleum coke, at a temperature in the range of from 1000.degree. C. to 1800.degree. C. and at a pressure in the range of from 0.1 MPa to 5 MPa in a reactor vessel with the use of an oxygen containing gas, wherein the particulate solid fuel is introduced into the reactor vessel in the form of a dispersion of particulate solid fuel in a gas such as an inert gas or syngas, or in the form of a dispersion of particulate solid fuel in a liquid such as residual oil or water.
In addition thereto, synthesis gas can be produced by partially oxidizing a liquid fuel, such as alcohol or a liquid hydrocarbon, in particular residual oil. The liquid fuel is partially oxidized at a temperature in the range of from 1000.degree. C. to 1800.degree. C. and at a pressure in the range of from 0.1 MPa to 8 MPa in a reactor vessel with the use of an oxygen containing gas, wherein the liquid fuel flowing into the reactor vessel is disintegrated with the use of oxygen containing gas.
Furthermore, synthesis gas can be produced by partially oxidizing in a reactor vessel a gaseous fuel such as gaseous hydrocarbons, in particular petroleum gas or natural gas, at a temperature in the range of from 1000.degree. C. to 1800.degree. C. and at a pressure in the range of from 0.1 MPa to 6 MPa with the use of an oxygen containing gas.
In this specification and in the claims the term "oxygen-containing gas" will refer to air, steam or oxygen, and the term "residual oil" will refer to a residual product that remains after application of a separation method such as, distillation or extraction on, for example, crude oil, tar sand, shale oil or coal extracts.
Synthesis gas will be produced near or at a crude oil refinery because the produced synthesis gas can directly be applied as a feedstock for the production of middle distillates, ammonia, methanol or as a fuel gas, for example, for heating the furnaces at the refinery or more efficiently for cogeneration of electricity and heat with load following electricity demand. Moreover, use can be made of the less valuable fuel products of the refinery.
If synthesis gas is produced by partially oxidizing a gaseous fuel, use can be made of refinery gas or of the gaseous hydrocarbons produced as a by-product of a synthesizing process. If synthesis gas is produced by partially oxidizing a liquid fuel, use can be made of residual oil and a limited amount of gas, for example a gaseous hydrocarbon, in order to disintegrate the flow of residual oil into the reactor vessel. If synthesis gas is produced by partially oxidizing a particulate solid fuel use can be made of particulate carbonaceous material dispersed in gas, in residual oil or water. However, in order to obtain a pumpable slurry only a limited amount of particulate carbonaceous material can be mixed with the liquid.
The above methods for producing synthesis gas, however, do not offer a large amount of operating flexibility because, in order to obtain a pumpable slurry, only a limited amount of particulate carbonaceous material can be dispersed in the liquid. Further the H.sub.2 /CO ratio of the syngas can only be slightly varied without varying the amount of moderator gas.
Further, it is already known to produce synthesis gas by introducing into a reactor vessel separated from each other at leas two different fuels from the group which comprises particulate solid fuel, liquid fuel and gaseous fuel, and allowing the fuels to oxidize partially inside the reactor vessel with the use of an oxygen containing gas.
In particular, the invention relates to a simultaneous gasification process as described in the foregoing, wherein (heavy) residue feedstock and a hydrocarbon gas (e.g. methane) are suitable to be used as fuels and wherein the liquid (or solid) and/or gaseous hydrocarbons can be supplied in any ratio. In such a process less moderator and oxidizer is required to achieve a specific H.sub.2 /CO ratio in the syngas.
In order to obtain an excellent gasification process it is necessary to ensure fine atomization of the liquid and good and rapid contacting or mixing of the fuels oxygen-containing gas and the moderator.
It is an object of the invention to provide a process for partial oxidation of a liquid or solid and/or a gaseous hydrocarbon-containing fuel wherein in situ fine atomization of the liquid is obtained or rapid dispersion of the solid. It is another object of the invention to provide a process for partial oxidation of a liquid or solid and/or a gaseous hydrocarbon-containing fuel wherein a good and rapid mixing or contacting of oxygen, fuels and moderator is obtained and pre-ignition or flame-flash-back to the burner internals is prevented.
It is another object of the invention to provide a process for gasification wherein economic process conditions (for example reduction of supply moderator gas and oxygen and reduction of soot carbon production) are achieved with a sufficiently long burner-lifetime.